The present invention relates to a photoelectric detecting apparatus and more particularly to a photoelectric detecting apparatus with which a pattern that diffracts light in a predetermined direction can be read out without noise.
Such type of photoelectric detecting apparatus which reads out a pattern that diffracts light in a predetermined direction is the subject of our prior application, U.S. Ser. No. 790,072 assigned to the assignee of the subject application, filed on Apr. 22, 1977.
The present invention relates to an improvement of the apparatus disclosed in the above-mentioned prior patent application. The improvement made by the pesent invention resides in that the apparatus of the present invention enables reading out of a pattern that diffracts light in a predetermined direction without noise.